Different Types of Viruses
Computer Viruses There are many different types of computer viruses. If we know and understand how viruses work, we can know and understand ways to prevent them. One type of virus is a macro virus. A macro virus infects an application or program with a macro, like Microsoft Word or Excel. It is spread when these files are emailed or uploaded to networks. Another type of virus is a memory resident virus. These viruses fix themselves inside a computer’s memory, usually in RAM. Every time the operating system runs, they are activated and spread to all opened files. Another type of virus is an overwrite virus. Overwrite viruses delete information in the files of a computer, rendering them useless. Another type of virus is a direct action virus. These viruses are also known as logic bombs. Logic bombs are viruses that are triggered when certain logical conditions are met. These conditions could be opening a file or starting a program a certain number of times. A directory virus infects a computer’s directory and changes the file path that indicates the location of the file. Another type of virus is a web-scripting virus. A web-scripting virus hides in the code of webpages and infects unsuspecting visitors to the webpage. A multipartite virus infects many different file types to try to confuse antivirus programs. FAT viruses infect a computers file allocation table (FAT). The FAT stores file location and available space information. Companion viruses attach themselves to other files once they are inside a computer. Another type of computer virus is a polymorphic virus. These viruses usually infect files on a computer and change their own code every so often to make it difficult for antivirus programs to locate their signature. An email virus is spread via email. Once in a system, it distributes itself to the email addresses in the user’s address book. A browser hijacker virus usually enters a computer through a voluntary download. It redirects users to certain sites regardless of the site they wanted to visit. Lastly, boot-sector viruses infect the master boot record on a computer’s hard drive. Boot-sector viruses originally became popular when floppy disks were needed to boot up a computer. These viruses, now usually transmitted through a flash drive, execute when a computer boots up, sometimes even before antivirus software can load, making them very dangerous to computers. Worms and Trojan Horses There are some programs that technically are not computer viruses, but they are just as if not more debilitating to a computer system. These programs will be discussed in this section. One of these programs is a worm. A worm is different from a virus because a virus requires human interaction to spread, and a worm does not. Worms are able to spread on their own through email and network connections. Thus, worms can spread much quicker than viruses. Another non-virus program that behaves similarly to a virus is a Trojan horse. A Trojan horse is a program that looks useful, but inside it is deadly. It could be in the form of a game or other application program. However, when the user downloads the program, it allows hackers to take control of his or her computer. By: Evan Beiler References Make Use Of Types List